Urban youths at high CVD risk who exhibit agonistic (AG) behavior and increased vascular resistance under youths at high agonistic (AG) a structured social challenge have elevated ambulatory blood pressure (ABP) in the natural environment. Evidence suggests this AG pattern is related to: (a) impaired emotion regulation (including suppression of vagal tone); (b) increased interpersonal conflict; and (c) increased insulin resistance; and thus may constitute a pathway via which chronic exposure to stressful social environments contributes to CVD. We will evaluate these possibilities by testing hypothesized relationships between the AG pattern, CV reactivity, and emotion regulation / vagal suppression under social challenge, interpersonal events recorded via electronic diaries, ABP, and indices of metabolic syndrome (fasting insulin, fasting glucose, lipid profiles, central body obesity) in Black and White adolescents from a range of SES backgrounds. During the 4 year project, a total of 1800 entering Grade 9 youths in 2 urban public high schools will be screened on resting BP, height, weight, and family history of CVD; 440 will participate in the proposed studies (equal numbers of males, females, Blacks, and Whites). Study 1 (Years 1 - 2) will measure AG behavior, emotion regulation / vagal suppression under social challenge, daily interpersonal stressors, ABP and metabolic syndrome indices in 240 participants to test the hypothesis that youths who exhibit the AG pattern and impaired emotion regulation /vagal suppression under challenge also exhibit more frequent interpersonal conflict recorded by electronic diary (7-day record), elevated ABP recorded over 48 hours during the same interval, and elevated levels of metabolic syndrome indices. Study 2 (Years 1 - 4) will follow 200 participants for 4 years to determine if the AG pattern and / or impaired emotion regulation / vagal suppression under social challenge are associated with higher levels of BP tracking and metabolic syndrome indices. Study 3 (Years 2-3) will evaluate the cross-situational consistency of the AG pattern and emotion regulation by collecting sociometric data from the teachers and peers of participants in Studies 1 and 2. Study 3 data will be used to test the hypotheses that the associations between the AG pattern / emotion regulation, interpersonal conflict, and CVD risk indices is partly mediated by youths' social environments. Possible moderating effects of urban stressors (neighborhood disorder, exposure to violence) will be included in these analyses.